This invention relates broadly to equipment and processes for breaking up concrete, asphalt and other pavement surfaces and, more particularly, pertains to a drop hammer arrangement which is conveniently attached for movement on a loader machine such as a skid steer.
Pavement surfaces comprised of concrete, asphalt and the like occasionally need to be partially or completely removed with the aid of various construction equipment. One type of impact device in widespread use for breaking up and demolishing smaller areas of pavement surfaces is a pneumatic, manually-operated, jack hammer. For larger expanses of pavement to be broken, it is common to equip a loader, such as a backhoe or skid steer, with an impact hammer attachment. In each case, it is necessary to supply an air compressor or separate power source to operate the jack hammer or impact hammer. In addition, there is a significant amount of vibration and fatigue inflicted on the hammer operator and the environment is affected by the large volume of dust particles emanated into the air. Other problems associated with the use of conventional hammers include a high noise factor and the periodic need to fix leaking oil fittings or repair air hose ruptures.
Other types of dedicated demolition equipment are available for breaking up concrete and other hard pavement surfaces. However, such special purpose devices are expensive to acquire, operate and maintain, and are often not practical for contractors during occasional demolition work.
Several other loader-mounted, demolition apparatus are known which use swinging hammer heads and employ various spring arrangements to impart whipping action or provide a cushioning effect. These apparatus have been generally over-complicated, require significant movement of their loader device for operation, transmit vibration and shock to the human operator and are not always easily mounted on their loaders.
Accordingly, it is desirable to provide a demolition hammer which has a simplified structure and a cost which is affordable to small sized contractors. Such demolition hammer should be capable of easy attachment to any skid steer loader and of establishing a resonant vibration such that cracking of pavement occurs throughout a large area. In addition, the demolition hammer should employ a spring arrangement which not only has the ability to return a hammer with gravity motion to an impact point and increase the speed of the return, but also relies upon the springs to absorb shocks and vibrations so they are not felt by the operator.
It is one object of the present invention to provide an apparatus and method for demolishing pavement wherein a lower spring is utilized to accelerate a hammer handle and hammer head towards an upper spring, the hammer handle and the hammer head returning to an impact point on a pavement surface either by gravity or acceleration from the upper spring.
It is another object of the present invention to provide an apparatus and method for demolishing pavement wherein the apparatus may be quickly and universally mounted upon a skid steer loader without any electric, hydraulic or pneumatic connections.
It is also an object of the present invention to provide an apparatus and method for demolishing pavement which has a low noise factor and is operator friendly causing no fatigue on the human operator.
It is an additional object of the present invention to provide an apparatus and method for demolishing pavement which can deliver variable impacts at distances remote from the skid steer loader.
It is a further object of the present invention to provide an apparatus and method for demolishing pavement which is less expensive and less complicated than those of the prior art.
In one aspect of the invention, a pavement demolition hammer is removably fastened to a loader. A mounting plate is securable to the loader, and a framework is attached to the mounting plate and provided with a lower spring and an upper spring spaced from the lower spring. A hammer handle has a proximal end pivotally mounted to the framework for swinging movement between the lower spring and the upper spring, and a distal end is equipped with a hammer head adapted to engage the pavement. The loader applies a moving force to the mounting plate such that the lower spring is accelerated against the bottom of the handle causing the handle and the hammer head to swing upwardly from a pavement surface to be broken towards the upper spring, the handle and the hammer head returning to the pavement surface either by gravity or acceleration from the upper spring against the top of the handle in a manner that the hammer head impacts and demolishes the pavement surface. The mounting plate is a generally rectangular, planar surface having a V-shaped bracket at its upper end, and a rearwardly extending lip with a pair of spaced apertures at a lower end, the bracket and the lip being manually engagable with an adapter plate on the loader. The framework includes a horizontally extending fork bottom disposed perpendicularly and forwardly of the mounting plate, a vertically extending fork top rising from a rearward end of the fork bottom along a forward surface of the mounting plate, and an upwardly and forwardly extending fork extension connected to an upper end of the fork top. A forward end of the fork bottom carries a generally cylindrical, lower coil spring, and a forward end of the fork extension carries a generally cylindrical, upper coil spring. The framework further includes a pair of parallel, spaced apart side plates, each side plate being attached to the fork bottom, fork top and fork extension. The hammer handle is disposed to swing between the side plates. The hammer handle is provided with an upper spring plate engagable with the upper spring, and a lower spring plate engagable with the lower spring. The hammer handle is normally supported on the lower spring. The hammer head has a generally cylindrical configuration with a downwardly depending impact point. The hammer head extends beyond the forward end of the fork bottom.
In another aspect of the invention, a pavement demolishing hammer includes a loader having lifting arm structure, a hydraulic cylinder carried on the lifting structure and an adapter plate including a top end pivotally mounted to the hydraulic cylinder and a bottom end pivotally secured to the lifting arm structure, the bottom end provided with a spring loaded pin. A framework includes a mounting plate with a bracket at an upper end and an apertured lip at a lower end. The mounting plate bracket is engagable with the top end of the adapter plate and the spring loaded pin is engagable with the apertured lip. The framework further includes a horizontally extending fork bottom disposed generally perpendicularly to the mounting plate, a vertically extending fork top to which the mounting plate is secured, and an upwardly and forwardly extending fork extension connected to the fork top. A generally cylindrical, lower coil spring is disposed on the fork bottom and a generally cylindrical, upper coil spring is located on the fork extension. A pair of spaced apart, side plates is provided, each being attached to the fork bottom, fork top and the fork extension. A hammer handle has a rearward end pivotally attached to the fork top for pivotal movement between the side plates and between the upper spring and the lower spring, and a forward end provided with a hammer head adapted to engage the pavement. Selective actuation of the hydraulic cylinder moves the mounting plate and framework such that the lower spring is accelerated against the bottom of the handle causing the handle and hammer head to swing upwardly from the pavement towards the upper spring. The handle and the hammer head return to the pavement either by gravity or acceleration from the upper spring against the top of the handle in a manner that the hammer head impacts the pavement.
In yet another aspect of the invention, there is contemplated a method of demolishing pavement including the steps of a) providing a framework with a lower spring and an upper spring spaced from the lower spring; b) providing a hammer handle having a proximal end pivotally mounted to the framework between the lower spring and the upper spring, and a distal end equipped with a hammer head adapted to engage the pavement; and c) moving the framework such that the lower spring is accelerated against a bottom of the handle causing the handle and the hammer head to swing upwardly from a pavement surface towards the upper spring, the handle and the hammer head returning to the pavement surface either by gravity or acceleration from the upper spring against a top of the handle in a manner such that the hammer head impacts and demolishes the pavement surface.
Various other objects, features and advantages of the invention will be made apparent from the following description taken together with the drawings.